1. Field of the Invention
The present invention relates to solids and free oil/water separation devices. More particularly, the present invention relates to a pre-cast unitary or modular assembly forming a pit for the pretreatment of water in a washpad installation for construction equipment and the like.
2. Description of the Related Art
Recent legislation has imposed strict limitations on the release of pollutants. This is particularly true in sensitive watershed areas such as that for the Chesapeake Bay watershed area. Construction equipment, road building equipment, farm equipment, and the like tend to collect oil and grease on their surfaces, along with dust and dirt, some of which clings to the oil-covered surfaces. It is necessary to periodically wash this equipment with pressure washers, resulting in wash water polluted with dirt, gravel, stones oil, and greases. It is also desirable to recycle the wash water for use in the pressure washers.
In response to the environmental requirements, it has become common practice to provide a drive-down pit for separating the wash water from dirt, stones, and gravel by settling, and oil and grease by consumption with enzymes or use of skimmers. This pretreatment of the wash water is necessary, regardless of the type of equipment being used for the recycling and/or discharge of the wash water. Such pits have a primary separation section where stones, gravel, and clumps of dirt are allowed to sink to the bottom. It is necessary to periodically remove such coarse material by providing a ramp for driving down a front-loading tractor into the water-containing pit and removing this material by manipulating the bucket of the tractor and backing out of the pit up the ramp.
The free oil and grease float to the water surface and is captured and then consumed by enzymes placed in table form in the pit or skimmed from the pit and removed for proper disposal. The enzymes are effective during summer months, while skimming is used in colder weather. Pretreated water is pumped from the pit as dirty water drains into the pit from the wash pad. The pretreated water is further cleaned by various types of separation equipment to be recycled to the pressure washers or discharged.
It typically takes two to three weeks to build forms and pour the concrete to complete the construction of the floor, walls, and ramp of such a pit, costing valuable labor time and delaying the use of a wash installation. Water leakage is a problem due to the multiple pours required, which may undermine the pit. It would be desirable to provide a unitary or modular pit system which can be customized for any pretreatment requirements and which can be quickly installed with the elimination or minimization of concrete pouring. Such a system would eliminate the need for building concrete casting forms and eliminate water leakage.
Thus a pre-cast drive-down pit system solving the aforementioned problems is desired.